I'd focus on the graphical site first as it's the most important thing in the website as it's the mirror of the site.. Then I'll go fo SEO because it brings the most important thing to websites which is traffic!

id say seo.When i first started out, i thought if my site looked good, it would be so easy to get visitors.But I soon found out thats not how it worked - and that it was much easier to have a good looking site than good seo,serps and traffic anyday